Hi. I’m new to your site and just trying to get some more info on VBAC. My daughter was a normal vaginal delivery. My second pregnancy(a surrogate pregnancy) was also a normal vaginal delivery. My third (also a surrogate pregnancy) was twins. I had planned to attempt a vaginal delivery with the twins with the support of my OB as long as Baby A was head down. Unfortunately she was breech and I ended up with a c-section at 36 1/2 weeks. My OB said if I want to attempt a VBAC for my next pregnancy I need to wait at least 2 years between the c-section and getting pregnant again. Is she just being cautious? Or is it really necessary to wait 2 years?
I cover interbirth intervals in great detail in my class. Here is a brief summary.
The short answer is: The range 18 – 24 months between pregnancies (delivery to conception) is the general recommended interval regardless of mode of delivery. It’s not just about the physical recovery from delivery (vaginal or cesarean.) It’s about the general stress and strain on our bodies/minds from the pregnancy, delivery, breastfeeding, and then caring for an infant.
Speaking specifically of VBACs, the concern mentioned is a possible increase of uterine rupture. ACOG’s VBAC guidelines associate short birth intervals with lower VBAC rates, but they do not mention a connection between short birth intervals and increased rates of uterine rupture. That is because the studies that ACOG cites include insufficient sample sizes and/or high rates of induction and augmentation.
Stamilio (2007) found the rate of uterine rupture when women got pregnant less than 6 months after their cesarean to be 3.05%, which was three times higher than their average rate of 0.9%. That is a very high rate of rupture, but keep in mind two things.
First, they only had 286 women who got pregnant within 6 months of their cesarean and that is not a large enough population to measure uterine rupture which occurs about 0.4% of the time in spontaneous labors after one prior low transverse cesarean (Landon, 2004). In order to accurately measure something that happens at that rate, we need about 5,000 women for that one category.
Second, 68% of those 286 women had their labors induced or augmented which we know increases the risk of rupture (Landon, 2004).
Stamilio (2007) stated [emphasis mine], “We hypothesized that short interpregnancy intervals may lead to altered wound healing and an increased risk of uterine rupture in patients who attempt a vaginal birth after cesarean. Our hypothesis is based on previous observational studies that suggest an association between short birth interval and increased adverse perinatal outcomes and wound-healing research that indicates that uterine smooth muscle tissue repair evolves over several months…. Importantly, there is radiographic and hysteroscopic evidence that cesarean scar development is incomplete as long as 6 or 12 months postoperatively.”
In other words, your scar is still healing and changing 6 to 12 months after your cesarean.
Stamilio (2007) as well as the other studies that have focused on uterine rupture by interpregnancy/interbirth intervals are rather small. It will be nice if/when larger studies are conducted so we have a better idea of the risk differential, if any, between births occurring less than 18 months post cesarean versus more than 18 months.
Does that mean that you should have a repeat cesarean if you get pregnant sooner? I don’t think we have enough information right now to make that determination.
Also keep in mind that since you have two prior vaginal births, your likelihood of VBAC success increases to over 85% (Landon, 2005).
You can read more by looking through my bibliography. Search for the terms ‘interbirth’ (time between cesarean birth and subsequent birth) and ‘interpregnacy’ (time between beginning of cesarean pregnancy and the beginning of subsequent pregnancies.)
Best of luck with your decision!
Stamilio, D. M., DeFranco, E., Pare, E., Odibo, A. O., Peipert, J. F., Allsworth, J. E., et al. (2007). Short Interpregnancy Interval: Risk of Uterine Rupture and Complications of Vaginal Birth After Cesarean Delivery. Obstetrics & Gynecology , 110 (5), 1075-1082.